Field of the Invention
The present invention relates to a vehicle headlamp for illuminating a light distribution pattern, for example a light distribution pattern for low beam (light distribution pattern for passing), toward a forward direction of a vehicle, the light distribution pattern having an oblique cutoff line at a cruising lane side and having a horizontal cutoff line at an opposite lane side, with an elbow point serving as a boundary.
Description of the Related Art
Vehicle headlamps of this type are conventionally known (Japanese Laid-open Patent Application No. 2007-109493 and Japanese Laid-open Patent Application No. 2007-172882, for example). Hereinafter, a conventional vehicle headlamp will be described. The conventional vehicle headlamp is a projector-type lamp unit, and is provided with a light source, an elliptical (convergent) reflector, a shade, and a projecting lens. Hereinafter, functions of the conventional vehicle headlamp will be described. When a light source is lit, the light from the light source is reflected by means of the reflector; a part of the reflected light is cut off by means of the shade. Afterwards, a light distribution pattern having an oblique cutoff line and a horizontal cutoff line is formed; and the light distribution pattern having the oblique cutoff line and the horizontal cutoff line is inverted longitudinally or transversely from the projecting lens, and is illuminated (projected) toward a forward direction of a vehicle.
However, the conventional vehicle headlamp is provided with a light source, a reflector, a shade, and a projecting lens, so that a large number of components are required, and there is a problem concerning downsizing, weight reduction, and cost reduction accordingly. Moreover, in the conventional vehicle headlamp, a relationship between the numbers of constituent light sources and optical elements is obtained as that of one constituent light source to three constituent optical elements, i.e., a reflector, a shade and a projecting lens (1:3). Thus, in the conventional vehicle headlamp, an error concerning a combination of variations in the three constituent optical elements, i.e., the reflector, the shade and the projecting lens occurs, and there is a problem concerning precision of assembling the three constituent optical elements, i.e., the reflector, the shade, and the projecting lens.
The present invention has been made in order to solve a problem concerning downsizing, weight reduction, or cost reduction and a problem concerning precision of assembling the three constituent optical elements, i.e., the reflector, the shade, and the projecting lens, which remain unsolved in the conventional vehicle headlamp.